(1) Field of the Invention
The present invention relates to a server, and more particularly, to a server for performing a process in compliance with a request from a client.
(2) Description of the Related Art
When exchanging information between a server and a client, a method is employed in which the client stores information (HTML (Hyper Text Markup Language) document etc.) downloaded from the server in a storage device thereof as history and when a “Back” button shown on the browser is operated, the client acquires and displays the information stored in the history, instead of making a request to the server.
This reduces unnecessary accesses to the server, making it possible to ease network congestion and also permitting smooth and speedy operation.
In cases where the Back button is used, however, there is a possibility that a request is sent from a page accessed earlier than the present time. In such cases, the server is unable to recognize the page which the client is then referring to, giving rise to a problem that a status error occurs.
Also, if, after registration for membership is applied for or an order for goods is placed on a member registration or ordering screen, for example, the Back button is operated to return to the same screen and the operation to apply for member registration or to place the order is repeated, a problem of double registration or double ordering arises.
A similar situation is also brought about by the cache function of the client side as well as the cache function of intervening proxy servers etc. that exist from place to place on the Internet.